AD-A235 416 MISCELLANEOUS PAPER GL-91-6

IlIIIlIII~llhil GEOPHYSICAL SURVEYS FOR LOCATIONSi OF A SUSPECTED ABANDONED MINE OPENING:

GRAYS LANDING SITE

by

Dwain K. Butler, Thomas B. Kean II

Geotechnical Laboratory

DEPARTMENT OF THE ARMY4, Waterways Experiment Station, Corps of Engineers

3909 Halls Ferry Road, Vicksburg, Mississippi 39180-6199

DTIC

YS ELECTEn- A PR251991

ES E

March 1991Final Report

4 : . "Approved For Public Release; Distribution Unlimited

LABORATORY Prepared for US Army Engineer District, PittsburghA T Pittsburgh, Pennsylvania 15222-4186

91 4 23i 011

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1. AGENCY USE ONLY (Leave blank) 2. REPORT DATE 3. REPORT TYPE AND DATES COVERED

I March 1991 Final report4. TITLE AND SUBTITLE S. FUNDING NUMBERS

Geophysical Surveys for Location of a Suspected MIPR CEORP-ED-9048Abandoned Mine Opening: Grays Landing Site

6. AUTHOR(S)

Dwain K. Butler, Thomas B. Kean II

7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) B. PERFORMING ORGANIZATIONREPORT NUMBER

USAE Waterways Experiment Station, Geotechnical Miscellaneous PaperLaboratory, 3909 Halls Ferry Road, Vicksburg, MS GL-91-639180-6199

9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSORING/MONITORINGAGENCY REPORT NUMBER

US Army Engineer District, PittsburghPittsburgh, PA 15222-4186

11. SUPPLEMENTARY NOTES

Available from National Technical Information Service, 5285 Port Royal Road, Springfield,VA 22161.

12a. DISTRIBUTION / AVAILABILITY STATEMENT 12b. DISTRIBUTION CODE

Approved for public release; distribution unlimited

13. ABSTRACT (Maximum 200 words)

The results of magnetic and electromagnetic surveys at the Grays landing Lock and Dam site onthe Monongahela River near Waynesburg, Pennsylvania, are presented. The purpose of the surveyswas to !ocate suspected abandoned mine openings in an area of the left abutment. Extensive subsur-face mining of the Pittsburgh Coal has been carried out in this area since the mid-to-late nineteenthcentury. Old mine maps and records indicate an 1882 drift opening into the Alicia No. 2 Mine in theright abutment area which could be under water during a 100-year.flood event. Exploratory drillingin the left abutment has failed to encounter the opening.

The area surveyed in rugged topographically and contains considerable surface metallic debriswhich represents possible noise sources for the geophysical surveys. While the geophysical surveyresults are complicated, there are anomalies on both the magnetic and electromagnetic data profileswhich are identifiable from one survey line to the next. An integrated geophysical anomaly map ispresented. Three anomalous zones are identified which trend into a steep slope. One of these(Continued)

14. SUBJECT TERMS 15. NUMBER OF PAGES

24Abandoned mine opening Geophysics 16. PRICE CODE

Electromagnetic survey Magnetic survey17. SECURITY CLASSIFICATION 18. SECURITY CLASSIFICATION 19. SECURITY CLASSIFICATION 20. LIMITATION OF ABSTRACT

OF REPORT OF THIS PAGE OF ABSTRACT

Unclassified Unclassified UnclassifiedNSN 7540-01-280-5500 Standard Form 298 (Rev 2-89)

Prescribed by ANSI Std 139-4S29S-102

13. (Concluded).

anomalous zones is consistent with the suspected location of the 1882 opening. Another anomalouszone may be associated with a concrete-lined drainage channel which is exposed on the riverwardside of the slope and disappears into the slope; this anomaly trends toward a more recent, known,sealed mine opening.

Preface

A geophysical investigation of an area of the left abutment

of Grays Landing Lock and Dam site was authorized by the US Army

Engineer District, Pittsburgh (CEORP), under MIPR No. CEORP-ED-

90-48, dated 31 July 1990. The work was performed during the

period October-November 1990.

Mr. Thomas B. Kean II and Dr. Dwain K. Butler, Engineering

Geophysics Branch (EGB), Earthquake Engineering and Geosciences

Division (EEGD), Geotechnical Laboratory (GL), US Army Engineer

Waterways Experiment Station (WES), conducted the field investi-

gations with the assistance of Mr. Gary D'Urso, Pittsburgh Dis-

trict. Messrs. Brian Greene --nd James Brown were the District's

points of contact for the work. This work was performed under

the general supervision of Mr. Joseph R. Curro, Jr., Chief, EGB,

Dr. Arley G. Franklin, Chief, EEGD, and Dr. William F. Marcuson

III, Chief, GL. This report was prepared by Dr. Butler.

COL Larry B. Fulton, EN, was Commander and Director of WES

during the publication of this report. Dr. Robert W. Whalin was

Technical Director.Aooession ForNTIS GRA&IDTIC TABUnannounced 0Justification

Distribution/Availability Codes

Avail and/orDist Special

A-I%

ContentsPacre

Preface . . . . . . .. .. .. .. .. .. ... .. .... . 1

Conversion Factors, Non-SI to SI (Metric)Units of Measurements .. ............ ......... 3

Background .. .................... ....... 4Geophysical Survey Program. ........... ......... 4Geophysical Anom~alies. ... ..................... 11Survey Results. ............ .............. 12Intergrated Anomaly Map and Assessment .... ........... 24

Conclusions. ... ...................... . 27

2

Conversion Factors, Non-SI to SI (Metric)Units of Measurements

Non-SI units of measurement used in this report can be convertedto SI (metric) units as follows:

Multiply BY To Obtain

feet 0.3048 metres

3

GEOPHYSICAL SURVEYS FOR LOCATION OF A SUSPECTED

ABANDONED MINE OPENING: GRAYS LANDING SITE

Background

1. The Pittsburgh District, US Army Corps of Engineers, is

constructing a lock and dam at a site known as Grays Landing on

the Monongahela River. Old mine records indicate openings to

access drift mining operations in the valley slope of the left

abutment side of the project. There are some indications that an

1882 mine opening (Alicia No. 2 Mine) accessed the Pittsburgh

coal seam (approximately 9 ft* thick) in the 1 ft abutment area,

and, if it existed, may not have been sealed. Since the

suspected mine opening might be below the 100 year frequency

flood pool level, it is important to verify its existence. An

extensive exploratory drilling program has failed to definitively

locate the 1882 opening, although at least one boring encountered

a void due to mined out coal. The present geophysical investi-

gations were conducted by personnel from the US Army Engineer

Waterways Experiment Station (WES), with the assistance of

District personnel, to locate the suspected 1882 drift opening.

This report gives guidance for location of exploratory borings or

trenches to verify the suspected opening location.

Geophysical Survey Program

2. Geophysical survey lines established in the left

abutment area specified by District personnel are shown in Figure

la. Various site features are also indicated in Figure la,

including approximate locations for the sealed mine opening and

the suspected 1882 mine opening. MS-23 and MS-24 are existing

exploratory borings. The survey line locations were determined

* A table of factors for converting non-SI units of

measurement to SI (metric) units is presented on page 3.

4

SITE MAP -- LEFT ABUTMENT AREA, GRAYS LANDING LOCK AND DAM

1-450-

0z 3 + 0 N

HAX +6 0

N + 0Z .390- a

b a 00 Approx. Location of 0+ Io Sealed Mine Opening-,,,, A 0 *

0 I +

0o 330 0 r- x + 0 MONONGAHELA

++ 0 RIVERxN

L % A 0N- + 0 II II I

.270" lv V IV 0(-) \ I + A * Survey Lines Az +(A) X + 0 *--- Approx. Location of Suspecteo

210- P\ 1882 Mine Opening+ A MS-24

a \MS-230 (approx.)

. To Tipple

150 1I50- II ' I I

250.00 350.00 450.00 550.00 650.00

EAST DISTANCE, FT (+ 1,389,000 = EASTING)

Figure la. Geophysical survey site map. Roman Numerals indicategeophysical survey lines. Symbols along survey lines

indicate flagged locations.

Figure 1. Geophysical survey site map and cross-section. (Continued)

5

li GEOPHYSICAL SURVEY AREA

840-

M L

~~LCL820- SH4ALE A

CLAYSTONE _____ FAG

UMES E -4E N OXIMATE EXISTING

_________ ____ LIM STONECLYW LSU F Es o ~~~ ~ A OA L Y ( M N N G )

LIMESTWETH LIMESLGRUNDSURACCLAAY SIrTSTONE

SISHALEWAH

zah APIOXMETSTPTOONEC

760.. LIETN ETH IETN0 ET.SITTN

0i 740-CA

0.

I,383001,3896400 I,'89EAST COORDINATE,* FEET

CROSS-SECTION AT LOCK STA. 8+65A

Figure lb. Cross-section AA'.

Figure 1. Geophysical survey site map and cross-section. (Concluded)

7

AA

A'

APPROXIMATE EXISTINGGROUND SURFACE4

z

.. CL -

______ ___7800

AL CL-..r CL EXISTING±±POOL EL. 763.0 &L

OF RO)C MLi**0 6

INDURATED CLAY - Sm -c

SHALEINDURATED CLAA74

SSILTSTONE

1,399,500 1.389ADO

NATE, FEET

LOCK STA. 8+65A LEGEND

PITIfIIIIN * SIASS. a.bS.MO * PS.*LAM11A

WWNSAIEL RIVER, F&.GRAYS LANDING LOCK AND DAM

EvIAfLUTON OF LEFT BANKILJ (ABWTWT SIDE)

CL IN±ZI.. GRSS SECTION AT LOCK STA. 8+6MA

SHLE3318 FIGURE 7

ed)

by a Pittsburgh District survey team, the approximate mine

opening locations were obtained from "Evaluation of Left Bank

(Abutment Side) Mine Seal and Cut Slope Requirements," Appendix D

of Design Memorandum No.4, Feature Design Memorandum, Grays

Landing Lock and Dam*, and other site features were obtained from

a Borings Plan/Topographic Map provided by District personnel.

Figure lb is a cross-section from the above reference along

cross-section AA' in Figure la. The individual survey lines are

identified in Figures la and 2 by Roman Numerals.

3. The survey lines were located by the geophysical survey

team and flagged at 20 ft intervals; flagged locations are indi-

cated in Figures 1 and 2 by different symbols for each line.

Geophysical measurements along lines I, II, V, and VI were ob-

tained at 10 ft intervals, where points between flags were

located by pacing. Lines I and II and lines V and Vl are located

along the sides of the Lower Road and the Upper Road, respec-

tively, as indicated in Figure la. Measurements along lines III

and IV, located on a steep slope, were obtained at 20 ft inter-

vals. The following tabulation summarizes the geophysical

surveys conducted at the site and gives approximate or "rule of

thumb" depths of investigation:

Approximate Depth of

Line Survey Method/Eauipment Investigation

I-VI Magnetic < 100 ft"

I-VI Electromagnetic (EM-31) < 18 ft

I/II Electromagnetic (EM-34) < 25 ftV/VI (Horizontal Dipole)

I/II Electromagnetic (EM-34) < 50 ftV/VI (Vertical Dipole)

"Orbital Engineering, Inc., October 1987, Prepared for USArmy Corps of Engineers, Pittsburgh District."This is a practical limit on depth of investigation due to

the length of the survey lines and not a physical limitation ofthe magnetic method itself.

9

0

r 4 ))

+C)0

0

+ 0 0 E

xU +0 -.

00

o 4 S

wi + 0 .s

cc 000

+ ~- Ex

0 + Zcr

+ L: 0

+ 0c

0> 0 00c< CD

z + 0I OD*x 4*0

0 jCo 0 + 0 T

x C+C

+ 0Cx J

00

0 0 c- -T

(ON IISVII =000'62' I +) Ld 'ZIONVISIG IV3

10

The designation I/II and V/VI for the EM-34 surveys indicates

that the actual measurements were acquired along the Lower Road

midway between lines I and II and along the Upper Road midway

between lines V and VI, respectively.

4. Magnetic field measurements were made with an EDA Omni

IV proton precession magnetometer. The magnetometer measures the

total earth's magnetic field strength in nanoteslas (nt). For

reference, the earth's total magnetic field strength at the site

is approximately 55,000 nt. Electromagnetic surveys were con-

ducted with the Geonics EM-31 and EM-34 instruments. The EM-31

is a one-man portable instrument with transmitter and receiver

coils separated by 3.66 m (12 ft) in a fiber glass boom; the

instrument operates at 9.8 Khz. The EM-34 is a two-man portable

instrument with separable transmitter and receiver coils. Stan-

dard coil spacings for the EM-34 are 10, 20 and 40 m (approx-

imately 33, 66 and 131 ft). Only the 10 m (33 ft) spacing was

used for the present work; the operating frequency at 10 m coil

spacing is 6.4 Khz. With the EM-34, measurements were made at

each location with the coils horizontal, coplanar (called the

vertical dipole mode), and with the coils vertical, coplanar

(called the horizontal dipole mode). The EM instruments measure

an apparent electrical conductivity (= 1/resistivity) of the

subsurface in millisiemen/meter (mS/m).

Geophysical Anomalies

5. The strategy of the geophysical surveys is to detect

anomalies relative to background which may indicate the presence

of abandoned mine openings. The type of geophysical anomaly

represented by the opening and access drift will vary depending

on its present condition, i.e., the nature and extent of the

filling material. It is likely that the access drift will

contain metallic debris, perhaps even rails going into the old

mine workings. It is unlikely that the access drift is com-

pletely filled. The filling material is likely soil, rock

fragments, and assorted wood and metal debris, which may have

11

higher water content than surrounding rock. The combination of

metallic debris and higher water content will result in high

magnetic and high conductivity anomalies for the filled portion

of the access drift relative to the surrounding undisturbed soil

and rock. For the case of metallic debris in an otherwise

unfilled access drift, there will still be a high magnetic

anomaly; but, depending on the amount and depth of metal, there

may or may not be a discernible conductivity anomaly. In any

event, for the geological conditions at the site, magnetic

anomalies can be considered to be due to buried or exposed

metallic objects.

6. The site presents considerable complications to the

application and interpretation of geophysical surveys. There is

considerable topographic variation in the survey area. Magnetic

surveys are not particularly affected by topography, but the

electromagnetic methods can be significantly affected. The EM-34

in the horizontal dipole mode is particularly sensitive to

topography and very near surface variations. Topographic sensi-

tivity also depends on the coil orientation relative to the topo-

graphic variations. The EM-31 boom and the EM-34 coils are

oriented along the survey lines, approximately parallel to topo-

graphic contours, for all measurements at this site. Another

complication of the site is the presence of surface metallic

debris that can affect both magnetic and electromagnetic

measurements.

Survey Results

7. Data for survey lines I, II, V, and VI are presented in

Figures 3-10. The data are plotted versus distance measured

along the line during the geophysical surveys; layout of the

lines in plan is shown in Figures 1 and 2. Data for lines III

and IV are not shown as profile plots due to the larger measure-

ment spacing and shorter line lengths; the data were utilized in

plan maps used to construct geophysical anomaly maps discussed

below. Note that the EM-34 data (10 m coil spacing) for lines I

12

000LO

0.

00060

00 LC"cc

"0

LLT >%

10

~L

-C)

00o 00

0 0 0

00 04 0LO 0r LO

SV]S11iON N 'HiON3 diS GT]]I]

13

0

It,

04J

-0

0

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LOI V)-q

SV S1iON 'HONI JIS(1111-

14.

0

0

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0060CNJ

-00C;C

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L0UL0 S

00

00

SV]SIIIONVN 'HION3 1IS G1AI

15

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LLC~)z G

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05

-06

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0 0:0 0) cy

SV1IS31ONVN 'HiON3 diS Gui1d

16

00

C U54-O

oo o

040

W1S w w ainCNO

17-

0

0.0

0

00

0 I

cv, 0

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UJ )

ftu

0 C0-* - C4

M/S t SClin(N

180

0

0V).

00

00

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CN c

00

4 0

0

0 0

0. F-E

0 --

o 0

LO N

N/Sw )dl~lonGNE

19C/

00

0.0

C1

SS

9v V0

w LO

0

*0

CIO NoSE

w 0

00

C Cb

o/S i~lo(IO

N 20

and II and for lines V and VI are identical, since the EM-34

surveys were conducted midway between lines I and II and between

lines V and VI. The magnetic and electromagnetic survey results

will be discussed separately, and then an integrated anomaly map

presented.

Magnetic survey results

8. Variation of the magnetic field strength with time,

during the survey, was negligible. The field strength values in

Figures 3-6 are the measured total magnetic field strengths minus

50,000 nT. Results of the magnetic survey exhibit significant

variation along each of the survey lines. Due to their close

proximity, lines I and II are qualitatively similar with regard

to number and location of maxima and minima. Likewise, lines V

and VI are qualitatively similar. There is also some qualitative

similarity between the two sets of survey lines; this similarity

is indicated in Figures 3-6 by letter labels assigned to the

major profile maxima. It appears that the features causing the

magnetic anomalies are elongated and pass under the survey lines

more or less perpendicular to the lines, consistent with the

suspected drift access into the abandoned mine. The qualitative

similarity of the anomalies on the four survey lines insures that

the anomalies are caused by subsurface metallic features and not

scattered surface metallic debris. One qualitative difference

between the two sets of magnetic survey data is that overall the

magnetic field strength for survey lines I and II increases with

increasing distance along the profile line while the data for

lines V and VI decrease with increasing distance. This quali-

tative difference may be due somehow to the fact that the surface

elevation increases with distance along I and II but decreases

with distance along V and VI.

9. The numerous maxima and minima along the relatively

short survey lines present an interpretation problem, since the

anomalies overlap. Depending on the depth, orientation and shape

of the object causing the magnetic anomaly, the actual profile

locations of object "centers" can vary from directly under the

21

anomaly maxima to a location under the point of maximum rate of

change (slope) (approximately midway) between a maximum and the

adjacent minimum located to the north. Closely spaced, sub-

surface metallic objects produce magnetic anomalies which

overlap, and thus the individual magnetic anomalies cannot be

observed completely. Anomaly locations are specified in such a

way, i.e., in bands, that this range of possibilities is in-

cluded; this fact must be remembered when locating boreholes or

excavations. Figure 11 is the magnetic anomaly location map,

where anomaly bands are indicated and labeled to correspond to

anomalies identified in Figures 3-6. Within the bands, locations

of the anomaly maxima and points of maximum slope are indicated.

Electromagnetic survey results

10. The electromagnetic survey results, Figures 7-10, do

not have the large, nearly periodic sequences of maxima and

minima exhibited by the magnetic field data. Figures 7 and 8

show a large, broad response for the horizontal dipole EM 34

response (indicated by the horizontal bar in the figures); this

response, which is not as evident (if at all) in Figures 9 and

10, is considered to be due to topographic effects on the data

(sharp dropoff on one side and steep slope on the other side of

the survey line). There is no evidence to support such a large

conductivity value, since both the EM 31 and the vertical dipole

EM 34 data consistently show much lower conductivity in this

region of the survey line. All of the data in Figures 7 and 8

are consistent in exhibiting the anomaly indicated by the arrow;

the anomaly has the classic appearance (maximum, minimum,

maximum) produced by crossing a very conductive object, even

tending to become negative directly over the object. The object

causing this anomaly (at the arrow) is shallow (less than 18 ft,

since it produces such a prominent effect on the EM 31 response)

and must be large in size and possess a high conductivity (since

the effect on the EM 34 is significant and the conductivity

measurements tend to go negative). A high conductivity anomaly

is present near the 240 ft profile position (indicated by the

22

00 -0

00 Ci)

+ 00

x

X~ + *0

4 0

V 0 2%0Q

0 0........ U-

- 00r~

0 0

C)C

I- 6'-

0U

+~of

-~~ -i-urn<

0 C)

to~ .0

(ON lISV] 00OO'629 'L+ Ii ']DNVISIG ISVi

23

vertical line) in Figures 7-10; in Figures 7 and 10, the anomaly

is indicated by the vertical dipole EM 34 data but not obviously

by the EM 31 data, while in Figures 8 and 9, the anomaly is

indicated by both the EM 31 and the vertical dipole EM 34 data.

Figure 12 indicates anomalous areas in plan from an analysis of

the electromagnetic data.

Integrated Anomaly MaD and Assessment

11. Figure 13 is an integrated anomaly map. The three

anomaly areas indicated represent an integration of the results

of the magnetic and electromagnetic results. The anomalies are

defined by magnetic and electromagnetic highs; thus the anomalies

are caused by subsurface features which co! in metallic debris

or structures and material that is otherwise electrically

conductive. Anomaly area I is locatcT appropriately to be

associated with the suspected 188z opening, which is indicated Gn

the figure. Anomaly I has a complex structure but may just

indicate a large, fornmer opening into the slope which narrowed to

a smaller adit accessing the interior of the mine. Anomaly I

also correlates with a structure passing under the lower road,

which can be observed exposed on the riverward side of the lower

road. The structure could be the remnant of a conveyor or

support system associated with a mine opening.

12. Anomaly II may be associated with structures passing

through the slope and connecting with the sealed opening in some

manner. There is a concrete-lined, steel grate-covered drainage

tunnel emerging from the slope and passing under the lower road

approximately at location 185,330 N. This drainage tunnel

contributes to the overall anomaly and may have been associated

with the sealed opening. The appearance of the slope face in the

vicinity of and between anomalies I and II indicates the possi-

bility that a substantial portion of the exposed Pittsburgh Coal

seam may have been removed to form a large opening into the mine

at one time.

1-. Anomaly III reflects the fact that the northernmost

24

* 00

x + 06

x 0+ CD0

x~ 0 *r

C-:0

+ 1-

0 0 j

(J x + cc I0 0-

< 0 >

+ E* 0 0

0 0 +U

z0 )

4 0 *(

0 E0

cc +

CM

C) z. )w 0F 0 4 ZW~ 0- zf ~

+ LO -

x - -

0 0

LO -

It 0

(ON LS VII 00OO'6C' +) iJ 'IIONVIS ic ISVi25

0E

0

0

+0x0

0 CL00

x0 + 0

0 0

+ C~

0 L 0

x +cc C) D

0 0LA.. 0

0O .. 0

0 C C

+ LOExU ell 4 O

0 2%0

z co0

+Vo *oLU 40 _-

- 0

00* 0

PO 0

(O~lSVI 00'2 ' +)I A 3JNiSIOiS0

+ - - 26

end of all the geophysical survey lines was anomalous. There is

a well-defined magnetic anomaly maximum on lines I, II, and V at

profile location 200-210 ft, while the electromagnetic conduc-

tivity increases steadily from profile location 200 ft to the end

of the survey lines. There is no known surface or subsurface

feature to correlate with this anomalous area.

Conclusions

14. Results of the geophysical surveys in the left

abutment area of Grays Landing Lock and Dam Site are less than

completely satisfying due to the complexity of the site in terms

of surface topography and surface metallic, cultural debris. The

surveys succeed, however, in mapping anomalous areas (Figure 13)

at the site. Two of the anomalous areas (I and II) trend

westward from the lower road area into the slope. One of these

anomalous areas (I) may be caused by the suspected 1882 mine

opening and its debris fill. If the anomalous areas are investi-

gated by exploratory drilling, the drilling should begin along

the centerlines of the areas and then successively offset by

approximately 10 ft to each side of the initial borehole, if the

initial borehole fails to encounter an anomalous feature. The

features causing the anomalies are likely less than 25 ft in

depth. However, conservatively, boreholes should be extended to

approximately 50 ft depth. Alternatively to drilling, trenching

would be an effective technique for investigating anomalous area

I for the suspected 1882 mine opening. The trench should be

located approximately along survey line II (along the west side

of the lower road), beginning about 10 ft north of MS-23 and

continuing north for approximately 70 ft or until evidence of an

opening is encountered.

27

DATE:

I AD-i235 416- HSA1 F IA OF - VS - ATIR

2U14CLASSMFED PEIT~IhT U 1 311~/ 1-6 F/G 17/6 H

I__END

lo-1.0 t 1 r

W6lIIu~uMis.

SUP PLEMENTAR'(

INFORMATION

DEPARTMENT OF THE ARMYWATERWAYS EXPERIMENT STATION. CORPS OF ENGINEERSP0. BOX 131

VICKSBURG. MISSISSIPPI 3010-031

R..Y TOAlTENTION OF

WESGG-F 24 April 1991

%I) No.1

GEOPHYSICAL SURVEYS FOR LOCATION

OF A SUSPECTED ABANDONED MINE

OPENING: GRAYS LANDING SITE

Final Report

Miscellaneous Paper GL-91-6

March 1991

1. Block 13, Abstract, Form 298:

Replace with enclosed, corrected page.

HYDRAULIC$ GEOTECHNICAL STRUCTURES ENVIRONMENTAL COASTAL ENGINEERING INFORMATIONLABORATORY LABORATORY LABORATORY LABORATORY RESEARCH CENTER TECHNOLOGY LABORATORY

91 5 07 065

I Form Appoved

REPORT DOCUMENTATION PAGE OMB No. 0ppoove

.6r~idir 11rOion= data suml~omn burde for his colectio Of iformaton stammtl to e .l~j o hou i r stx .,ibueddefg te timefor rviewin Iris h etheo r ofitthi

lof uafdtkcn including sugetiOns for reducing this burde nu. o for Infomation OpwetIon, end Serort 1215 JffmnonoDave HighWay. Suite 1204, Arlington, VA 22202,4302. and to the Office of Managem t and Budget. Paperwork Aeductin Project (0704-01U8), Wahington, DC 20503.

1. AGENCY USE ONLY (Leave l 2. REPORT DATE .MEPORT TYPE AND DATES COVEREDI March 1991 Final report_____________

4 TME AND SUBTITLE S. FUNDING NUMBERS

Geophysical Surveys for Location of a Suspected MIPR CEORP-ED-90-48Abandoned Mine Opening: Grays Landing Site6. AUTHOR(S)

Dwain K. Butler, Thomas B. Kean U

7. PERFORMING ORGANIZATION NAME(S) AND ADORESS(ES) S. PERFORMING ORGANIZATION

REPORT NUMBER

USAE Waterways Experiment Station, Geotechnical Miscellaneous PaperLaboratory, 3909 Halls Ferry Road, Vicksburg, MS GL-91-639180-6199

9. SPONSORING / MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSORING / MONITORINGAGENCY REPORT NUMBER

US Army Engineer District, PittsburghPittsburgh, PA 15222-4186

11. SUPPLEMENTARY NOTES

Available from National Technical Information Service, 5285 Port Royal Road, Springfield,VA 22161.

12a. DISTRIBUTION /AVAILABILITY STATEMENT 12b. DISTRIBUTION CODE

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13. ABSTRACT (Maximum 200words)

The results of magnetic and electromagnetic surveys at the Grays Landing Lock and Dam site onthe Monongahela River near Waynesburg, Pennsylvania, are presented. The purpose of the surveyswas to locate suspected abandoned mine openings in an area of the left abutment. Extensive subsur-face mining of the Pittsburgh Coal has been carried out in this area since the mid-to-late nineteenthcentury. Old mine maps and records indicate an 1882 drift opening into the Alicia No. 2 Mine in theleft abutment area which could be under water during a 100-year flood event. Exploratory drilling inthe left abutment has failed to encounter the opening.

The area surveyed is rugged topographically and contains considerable surface metallic debriswhich represents possible noise sources for the geophysical surveys. While the geophysical surveyresults are complicated, there are anomalies on both the magnetic and electromagnetic data profileswhich are identifiable from one survey line to the next. An integrated geophysical anomaly map ispresented. Three anomalous zones are identified which trend into a steep slope. One of these

(Continued)14. SUBJECT TERMS 15. NUMBER OF PAGES

24Abandoned mine opening Geophysics 14. PRICE CODE

Elomagnetc survey Magnetic survey17. SECURITY SSIICATIO . SEURITY CLASSIFMATION 1g. SECURITY CLASSIFCTION 20. LIMITATION OF ABSTRACT

OF REPORT OF THIS PAGE OF ABSTRACT

Unclassified Unclassified UnclassifiedNSN 7540-01-280-5500 Standard Form 298 (Rev 249)

Pre1cribed by ANSI $td lZW1250.-10?

13. (Concluded).

anomaloui zones is consistent with the suspected location of the 1882 openfn. Another anomalonzone may be ussociatd with a concretelined dranage channel which is exposed on the tiverwadside of the slope and diappea r no, the slope; this anomaly treads toward a more recent, known,sealed mine opening